MCH, a cyclic peptide, was first identified over a decade ago in teleost fish where it appears to regulate color change. More recently, MCH has been the subject of investigation for its possible role as a regulator of eating behavior in mammals. As reported by Shimada et al., Nature, Vol. 396 (17 Dec. 1998), pp. 670-673, MCH-deficient mice have reduced body weight and leanness due to hypophagia (reduced feeding). In view of their findings, it was suggested that antagonists of MCH may be effective for the treatment of obesity. U.S. Pat. No. 5,908,830 discloses a combination therapy for the treatment of diabetes or obesity involving the administration of a metabolic rate increasing agent and a feeding behavior modifying agent, an Example of the latter being an MCH antagonist. Further, MCH receptor antagonists may also be useful in the treatment of depression and/or anxiety. Borowksy et al., Nature Medicine, 8, pp. 825-830 (1 Aug. 2002).
WO 03/047568 discloses compounds having MCH antagonistic activity. A desired goal is to find compounds that have low Ki values and fewer side effects.